I've never tamed a lion, but I can safely say that improvisation would not be wise. Knowing the mind and temperament of the beast will be important when it is no longer of a size you can easily subdue. There are likely books written on the subject of lions, though I can't say whether or not they will include a section on training them.

As to the question of taking the creature hunting--if I have the time, it would be my honor to escort you. [For Cersei's sake, as much as Myrcella's. For his own sake, as well? Perhaps a little. At least it is a task easily accomplished. A knight is often called to such tasks. For all the hunting Robert did, Jaime accompanied him few enough times. Deliberately. Still, it is a task easily managed, and whatever uncertainty he might feel can be kept at bay.] And if his appetites prove to be too voracious, we'll figure something out. Above all, you must take care.

[De Chima is unwelcome news. Jaime's smile dips, slightly.]

Maurtia Falls. I was originally assigned to De Chima, but I found it too full of Starks and their allies. I can easily come to your city, and we can dine there. My registration with the government of this country allows me to use the porters to travel between the cities. You'll have that same right when you register.